EXPERT HELP NEEDED REGARDING SPEEDO.

[FiShLeGs]

i asked before,but still havent found out.
i got a twincam form japan,it has the digital dash.it is calibrated to read the speed,in miles and kms.there must be a way to change it from its current kph,over to mph.im guessing when they got to america they had to be sold reading mph?so it should be easy to do?
for our mot it must read kph and mph.
does anyone have an english version of the hand book,i only got the japanese one
my dash looks liek this